Something bothered me recently when I attended
an Orthodox Bar Mitzvah week-end. The Orthodox caterers were
serving food during Shabbat. They seemed to be working very hard
on the Shabbat. What is the halacha for preparing, serving,
and cleaning up during Shabbat? Thank you!

Dear Judith Subar,

On Shabbat, 39 categories of creative activities
are forbidden by the Torah. These include such things as cooking,
writing and building a fire. Other prohibitions were added by
our Sages to safeguard the sanctity and spirit of Shabbat.

As long as the caterer avoids any of these forbidden
activities, he is allowed to "work" on Shabbat. For example,
all food must be cooked in advance and kept warm on a stove that
was lit before Shabbat. He doesn't violate the spirit of Shabbat
either, because his efforts are Shabbat related.

Another issue is the Rabbinic prohibition against
earning wages on Shabbat. The Sages forbade earning wages for
a Shabbat activity, even if the activity itself is permitted.
They limited this prohibition, however, only to payment designated
specifically for work done on Shabbat. But if the pay
is part of a "package deal" which includes work done
during the week, such as setting up before Shabbat, then even
the Shabbat wages are permitted.